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<P class="title"><A NAME="HELPCommandsBenchmark"></A>"Benchmark" command<hr></P>

<P>Using "Benchmark" command you may compare performance of RAR compression
algorithm on different computers.</P>

<P>This command generates random data, which contain specially introduced
redundancy increasing load to processor and memory. Then data are passed
through RAR compression and decompression algorithms and output of
decompression algorithm is compared with source data. If any difference
found, WinRAR reports "Errors found - Yes" in the command window.
Such errors may indicate hardware problems like unreliable memory.
Also WinRAR displays a size of processed data and compression speed,
current and resulting, in kilobytes per second. You may use the resulting
speed value to compare RAR performance in different conditions. For example,
"Benchmark" command may be helpful, when you need to choose a new computer
and wish to know which one will compress data faster. General compression
algorithm in "Normal" mode with 32 MB dictionary is invoked, additional
filters and algorithms are disabled.</P>

<P>Using "Multithreading" option you can compare performance of usual
single threaded and multithreaded (optimized for multiprocessor architectures)
versions of RAR compression algorithm. It is also possible to specify
the exact number of threads and copy benchmark results to clipboard.</P>

<P>It takes some time to fill the compression dictionary, which is
empty in the beginning. Until it is done, the speed value is inconsistent,
so the command window starts to display the current speed only a few
seconds after activating. Resulting speed is displayed when collected
statistics is enough to get an accurate result. After the resulting speed
has been set, it is not changed more. Though source data are random,
their redundancy level and other parameters are always the same.
So this command will report practically the same current speed regardless
of execution time, provided that system load is not changing.</P>

<P>It is not guaranteed that different WinRAR versions will report
same compression speed values, so if you use this command to compare
performance of different computers, ensure that you run the same WinRAR
version in all tests. Also it is recommended to close other applications
before starting a benchmark.</P>

<P>"Benchmark" command is never finished automatically, you need to
cancel it manually. It does not use the hard disk, all operations are
performed in memory.</P>

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